ring/polyfill/
slice.rs

1// Permission is hereby granted, free of charge, to any
2// person obtaining a copy of this software and associated
3// documentation files (the "Software"), to deal in the
4// Software without restriction, including without
5// limitation the rights to use, copy, modify, merge,
6// publish, distribute, sublicense, and/or sell copies of
7// the Software, and to permit persons to whom the Software
8// is furnished to do so, subject to the following
9// conditions:
10//
11// The above copyright notice and this permission notice
12// shall be included in all copies or substantial portions
13// of the Software.
14//
15// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
16// ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
17// TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
18// PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
19// SHALL THE AUTHOR OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
20// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
22// IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
23// DEALINGS IN THE SOFTWARE.
24
25mod as_chunks;
26mod as_chunks_mut;
27
28pub use as_chunks::{as_chunks, AsChunks};
29pub use as_chunks_mut::{as_chunks_mut, AsChunksMut};
30
31// TODO(MSRV feature(split_at_checked)): Use `slice::split_at_checked`.
32//
33// Note that the libcore version is implemented in terms of
34// `slice::split_at_unchecked()`, and `slice::split_at()` was changed to be
35// implemented in terms of `split_at_checked`. For now, we implement this in
36// terms of `split_at` and rely on the optimizer to eliminate the panic.
37#[inline(always)]
38pub fn split_at_checked<T>(slice: &[T], i: usize) -> Option<(&[T], &[T])> {
39    if slice.len() >= i {
40        Some(slice.split_at(i))
41    } else {
42        None
43    }
44}
45
46// TODO(MSRV-1.77): Use `slice::split_first_chunk_mut`.
47#[inline(always)]
48pub fn split_first_chunk_mut<T, const N: usize>(
49    slice: &mut [T],
50) -> Option<(&mut [T; N], &mut [T])> {
51    if slice.len() >= N {
52        let (head, tail) = slice.split_at_mut(N);
53        head.try_into().ok().map(|head| (head, tail))
54    } else {
55        None
56    }
57}
ring/polyfill/slice.rs

ring/polyfill/
slice.rs
